Madonna's 14-year-old daughter arrived alone for the premiere of "Harry Potter and the Deathly Hallows" this week-sporting a skin-tight dress and dyed black hair. Isabel Wilkinson on the evolution of the youngest Material Girl.

At the premiere of Harry Potter and the Deathly Hallows on Monday night in New York, Sarah Jessica Parker strolled hand-in-hand with her 8-year-old son, Emma Watson posed on the red carpet with Daniel Radcliffe, and teen fans lined up to catch a glimpse of their favorite stars. But there was one tween who didn't fit in with the sea of Muggles: Lourdes Leon, Madonna's 14-year-old daughter, who slinked down the red carpet in a Band-Aid-tight minidress, flipping her new jet-black hair. For the first time, she wore dramatic makeup: smoky eye shadow, exaggerated black eyeliner, and pink lips. And there were booties, a cropped leather jacket, an Alexander McQueen skull scarf and glittering Union Jack clutch. She looked positively badass -- maybe a little too badass.

It's no secret that Lourdes is ahead of her time: She's always been impossibly chic, and not just for a teen. But this fall, she's taken a leap into adulthood as she turned 14, started high school, founded a clothing line, and attended a string of red-carpet events with her mother. Over the past few months she has been pushing, perhaps, the respectable boundaries for a 14-year-old in the public eye. This fall, she and Madge launched Material Girl, a line of clothes for tweens at Macy's that CEO Terry Lundgren said, through a spokesperson, was a financial "home run for the company." Their collection features sparkling hotpants, midriff-baring tops, leopard prints, and combat boots. As New York magazine's Alex Morris put it: "The Material Girl line is perfect for you if you are an NYU art major with a killer body" -- but this is a collection aimed at "juniors." The official face of Material Girl is Taylor Momsen, the 17-year-old platinum blond Gossip Girl star whose style includes real stripper heels and garter belts. As the brains behind the line, Lourdes blogs about stuff she loves -- praising thigh-high stockings and two-finger rings -- to provide design inspiration, and often models the clothes herself.

Her personal transformation has been gradual. Two years ago she was in a black knee-length dress and a pair of Mary Janes; this time last year she wore stockings and legwarmers as she strolled arm-in-arm with a friend. But this fall, Lourdes has gone vamp. On her first day of freshman year at LaGuardia High School, she wore leather ankle boots and a marijuana wristband. To several events, she's worn ripped stockings, chipped black nail polish, combat boots-and now, dyed black hair. According to Kimberly, who runs the celebrity blog Agent Bedhead and is the mother of a 10-year-old girl, 14 is just too young for such looks. "I feel like Lourdes wasn't dressing any worse than most 13-year-olds," she says. "But now, I have to wonder if she's hanging around Taylor Momsen a little bit too much. She's been sending the Lolita vibe a little bit since she's launched her line."

But even with Madonna as a mother, there are ground rules. "She can wear makeup when she goes to parties and special events," Madonna has said. "And ya know, there's always a little bit of a discussion about how short the skirt is ... or is there some cleavage showing. And I always say to her, do you want everybody to be staring at your breasts, or do you want people to talk to you?" Madonna also established a rule against dyeing her hair-until she was 14. As Lourdes wrote in her first blog post last year: "I'm 13 and I'll be 14 in October, so I can't wait for that because I am FINALLY allowed to dye my hair...THANK YOU MOTHER!!" But Kimberly wonders: "If she's dyeing her hair at 14, is she going to be looking for a nose job at 16? When's it going to stop? Her mother's Madonna, but I wouldn't let my daughter do that!"

Perhaps the biggest difference for Lourdes on the red carpet Monday was what was missing: Madonna herself. After tagging along with her mother at multiple premieres and galas, at Harry Potter, Lourdes was riding solo for the first time. "I get the feeling that Madonna is very protective of her and doesn't want her in the limelight a lot, but Lourdes likes being in front of the camera," says the head writer for the blog Celebitchy, who wanted to be identified only as "Kaiser." "I think Lourdes is growing up, but she has kid-like style. It's a little bit mature, but in a land where Miley Cyrus is flashing her v----, Lourdes is demure."

Isabel Wilkinson is an assistant editor at The Daily Beast based in Los Angeles.